1. Field of the Invention
The present invention relates to an electromagnetic clutch coil assembly provided at a compressor of an air conditioner for an automobile, and a manufacturing method thereof.
2. Description of the Related Art
In general, an air conditioning system for an automobile includes an air conditioner for cooling the inside of the automobile. The conventional circulation cycle of coolant in the air conditioning system of the automobile is as follows. The coolant in the state of a low temperature and low pressure enters in a vaporizer. When the coolant vaporizes at the vaporizer, heat outside the vaporizer is used so that the outside temperature is lowered. The coolant exhausting from the vaporizer is in the state of high temperature and low pressure. Then, the coolant is compressed by a compressor and enters in the condenser. The condenser condenses the coolant to make it in the state of high temperature and high pressure. The coolant turns to be in the state of low temperature and low pressure at an expansion valve just before entering in the vaporizer.
In the above air conditioner, the compressor is typically driven by the power of an engine of the automobile. A drive shaft of the compressor is connected to a pulley of a crank shaft of the engine by a belt and rotates thereby. An electromagnetic clutch is included in a compressor assembly so that the power can be selectively transferred to the compressor. That is, the electromagnetic clutch of the compressor can selectively transfer the power of the crank shaft to the compressor by connecting or disconnecting a disk detachably installed at a stopper plate by using a magnetic force of an electromagnet, to or from a pulley assembly.
FIG. 1 shows the structure of a typical compressor of an air conditioner for an automobile. Referring to the drawing, an electromagnetic coil assembly 12, a pulley assembly 13, and a disk and hub assembly 14 are sequentially assembled to a main body 11 of the compressor. Since the pulley assembly 13 is connected by a belt to a pulley of a crank shaft of an engine of the automobile, an idling state is maintained. When an electric power is applied to the electromagnetic clutch coil assembly 12, a magnetic force is generated by the electromagnet. Thereby, a disk of the disk and hub assembly 14 contacts a frictional surface of the pulley assembly 13. When the disk rotates, a drive shaft 11S of the main body 11 of the compressor rotates.
FIG. 2 shows the structure of the electromagnetic clutch coil assembly 12 of the compressor 10 of FIG. 1. Referring to FIG. 2, a coil winding 21 is inserted in a bobbin 22a and the bobbin 22a together with the coil winding 21 is inserted in a field core assembly 24 where a central hollow portion 23 is formed. Accordingly, the coil winding 21 is insulated by the bobbin 22a from the inner surface of the field core assembly 24. The coil winding 21 inserted in the field core assembly 24 is closed by a cover 22 having a central aperture.
In a conventional method of manufacturing the electromagnetic clutch coil assembly, first, the coil winding 21 is formed by winding a coil coated with an adhesive. Next, the coil winding 21 is heated at a high temperature and hardened by cooling. Then, the coil winding 21, the bobbin 22a, and the cover 22 are assembled in the field core assembly 24.
In the above conventional manufacturing method of the electromagnetic clutch coil assembly, lead wires connected to both ends of the coil winding of the electromagnetic clutch are damaged or short-circuited due to vibrations and high temperature of the automobile during the operation of compressor.
To solve the above-described problems, it is an object of the present invention to provide an electromagnetic clutch coil assembly and a manufacturing method thereof which can prevent the lead wires connected to both ends of the coil winding of the electromagnetic clutch from being damaged or disconnected due to vibrations and high temperature of the automobile.
To achieve the above object, there is provided a method of manufacturing an electromagnetic clutch coil assembly provided in a compressor of an air conditioner for an automobile, the method comprising (a) forming a coil winding by winding a coil coated with an adhesive, (b) heating the coil winding in a state of being pressed in a direction in which the coil winding is stacked, (c) hardening the coil winding by cooling the coil winding in the state of being pressed in a direction in which the coil winding is stacked, and (d) assembling the coil winding, a bobbin, and a cover in a field core assembly, wherein the adhesive between two neighboring coil layers in a direction in which the coil winding is stacked moves to a nearby empty space.
It is preferred in the present invention that, in (b) and (C), me coil winding is pressed by an air compressor in the direction in which the coil winding is stacked.
It is preferred in the present invention that, in (a), the coil is compacted by being extended by a tensile force so that the height of the coil winding decreases.
To achieve the above object, there is provided an electromagnetic clutch coil assembly provided in a compressor of an air conditioner for an automobile, comprising a coil winding formed by winding a coil coated with an adhesive and heated and pressed in a direction in which the coil winding is stacked, so that an adhesive between two neighboring coil layers in the direction in which the coil winding is stacked moves to a nearby empty space; and a bobbin, a field core assembly, and a cover assembled together with the coil winding.